I have a new machine where my established distro does not install - no problem with Fedora; so ... On my old machine, I have used BackupPC 3 for many years, Fedora 28 on my new machine proposes BackupPC 4, and I do not get it to work.

There is a basic problem: when Fedora-28 BackupPC starts, it immediately fails to run. The reason is that the Fedora package creates a /var/log/BackupPC directory which has ownership root:backuppc and access rights drwxr-x--- (0750); BackupPC necessarily fails and abandons as soon as it tries to create its log file on that directory. That is easy to fix, but (given that I only found a single thread on this forum that relates to BackupPC 4, and which does not refer to this issue) it makes me ask the question:
did anybody manage to use BackupPC 4 on Fedora 28?
After fixing this log-directory issue, I found (so far) 2 other problems that are not so evident to deal with:
  1. the authorisation for rsync access from the clients fails (with backuppc 3 I used anonymous access without problem) - that should not be difficult to fix, and
  2. the CGI access to the web interface does not work - probably an issue of the authorisation in apache, rather looks like a headache.

And a cheating question:
as a quick workaround for getting backup to work, would it make sense to dig out an old BackupPC 3 package - Fedora 27? - and make it run on 28?